The present invention relates generally to semiconductor device off-loading systems, and more specifically, to semiconductor device off-loading systems capable of handling and transporting a large number of semiconductor devices per hour.
Semiconductor device manufacturers generally manufacture semiconductor devices in large quantities in order to increase the efficiency of various production phases within the process. By increasing the efficiency of the production process, the marginal cost for producing each additional device is decreased. The efficiency of the production process is further increased by increasing the speed with which the semiconductor devices are produced. The speed at which semiconductor devices are produced is measured by the number of devices, or units, which can be produced per hour (UPH). This is generally referred to as the system xe2x80x9cthroughputxe2x80x9d rate.
A fundamental practice used for increasing the speed and efficiency of the semiconductor production process is to produce a large number of semiconductor devices simultaneously during each phase of an xe2x80x9cassembly-line typexe2x80x9d manufacturing process. This is accomplished, in part, by forming multiple semiconductor devices upon a wafer. Each of the following semiconductor processing stages are then designed to perform a respective processing operation multiple times for each of the devices within the wafer. After each semiconductor device is separated from the wafer, some production processes place the individual devices on frames which secure multiple devices in a matrix (i.e., in rows and columns). These frames allow many semiconductor devices to simultaneously undergo further stages of production.
Eventually, the production process must handle and transport (xe2x80x9coff-loadxe2x80x9d) individual semiconductor devices, which have been separated from a wafer or frame. In order to maintain the throughput rate for the production process, the systems for off-loading the semiconductor devices must be able to operate at a high throughput rate. Currently, off-loading systems transport packaged semiconductor devices one-at-a-time between production phases. This manner of transportation allows for an over-all system throughput rate of approximately 5000 units per hour (UPH). Unfortunately, at this rate, the off-loading system creates a bottle-neck in the overall production process. To compensate for the low off-loading rates, multiple off-loading systems may be utilized, however, the additional off-loaders would increase the cost of the production process and require extra space in the production facility. In light of the forgoing, an off-loading system capable of a high UPH would be desirable.
The present invention is directed to an off-loading system for a semiconductor manufacturing process which is capable of transporting a high number of semiconductor devices per hour. Generally, the off-loading system of the present invention transports devices at a high rate of speed by individually transporting multiple semiconductor devices from a matrix of semiconductor devices. The off-loading system, according to one embodiment of the invention, includes an array of suction tubes which are each able to pick up an associated semiconductor device from the matrix of devices and a pump which pulls air through the suction tubes to create a sufficiently low pressure within the suction tubes to allow each suction tube to pick up an associated device. In another embodiment of the invention, the off-loading system also includes a pin board which supports an array of pins configured to raise a selected array of the semiconductor devices to assist in picking up the selected array of devices from the matrix of devices. The invention may also include a control system which allows the off-loading system to transport only selected semiconductor devices of the matrix of devices.
In another invention described herein, a rack is described for use in staging a multiplicity of packaged semiconductor devices in parallel. In some embodiments, the rack includes multiple elongated rails which are supported upon a base. The rails form multiple channels through which the semiconductor devices travel so that they may properly enter a subsequent phase of the manufacturing process.
Another aspect of the invention pertains to a method for transporting semiconductor devices from a matrix of semiconductor devices during a semiconductor assembly process using the off-loading system of the present invention. The method includes picking up a selected array of semiconductor devices individually and simultaneously from the matrix and depositing at least one of the devices of the selected array onto a handling station. In one embodiment of the method, the selected array of the semiconductor devices is raised relative to the other semiconductor devices in the matrix in order to assist in picking up the selected array of packaged devices from the matrix.
In another embodiment of the method, the matrix of semiconductor devices is arranged in rows and columns and every other device, or every third device, within each of the rows and columns is picked up. The pickup process may be repeated such that all the semiconductor devices within the matrix may be off-loaded through multiple pick-up passes.
These and other features and advantages of the present invention will be presented in more detail in the following specification of the invention and the accompanying figures which illustrate by way of example the principles of the invention.